Project description:To investigate the subspecies level differences in the expression profiles of Streptococcus salivarius strains, we conducted the RNA sequencing analysis of Streptococcus salivarius strains.
Project description:Small distortions in transcriptional networks might lead to drastic phenotypical changes, especially in cellular developmental programs such as competence for natural transformation. Here, we report a pervasive circuitry rewiring for competence and predation interplay in commensal streptococci. Canonically, in model species of streptococci such as Streptococcus pneumoniae and Streptococcus mutans, the pheromone-based two-component system BlpRH is a central node that orchestrates the production of antimicrobial compounds (bacteriocins) and incorporates signal from the competence activation cascade. However, the human commensal Streptococcus salivarius does not contain a functional BlpRH pair and in this species, the competence signaling system ComRS directly couples bacteriocin production and competence commitment. This network shortcut might account for an optimal reaction against microbial competitors and could explain the high prevalence of S. salivarius in the human digestive tract. Moreover, the broad spectrum of bacteriocin activity against pathogenic bacteria showcases the commensal and genetically tractable S. salivarius species as a user-friendly model for natural transformation and bacterial predation.
Project description:Chlorhexidine (CHX) is a widely used antiseptic agent in dental care due to its broad-spectrum antimicrobial properties. This study focuses on the transcriptomic changes associated with chlorhexidine adaptation in oral Streptococcus salivarius (73_wt, 73_a), Streptococcus vestibularis (78_wt, 78_e), and Streptococcus mitis (93_wt, 93_d) using RNA sequencing.
Project description:Identification of proteins from extracellular vesicles isolated from Streptococcus salivarius. This work was financially supported by the National Science Centre, Poland (grant number 2021/43/D/NZ6/01464).
Project description:NIP and NrpR forms a pair for the transcriptional regulator in Streptococcus salivarius K12 (SAL). To explore the target genes regulated by the NIP-NrpR pair in Streptococcus salivarius K12 (SAL), we generated mutants in which the NIP or NrpR gene has been knocked down through complement recombination. Comparative transcriptome profiling of WT, ▲nrpR, and nip* mutant strains revealed that the sar BGC is the major regulatory target controlled by the NIP signaling pathway in SAL.
Project description:The human oral cavity is one of the most competing environments, considering the extent and diversity of the bacterial community that colonizes it, as well as the multiple stresses to which it is subjected. The commensal species Streptococcus salivarius is one of the first colonizers of the oral mucosa (tongue, gums, inner cheeks and tooth enamel) in infants and remains predominant throughout the life of an adult. In order to adapt to diverse and variable environmental conditions, S. salivarius triggers in a coordinated way two bacterial developmental processes: competence (acquisition of extracellular DNA and new genetic traits) and predation (secretion of cytotoxic molecule), via ComR, a transcription factor activatable by a "pheromone" peptide. Nevertheless, the activation of other transcriptional regulators can uncouple these 2 mechanisms to allow, for example, only the production of toxins without triggering the competence phase.
Project description:Streptococcus agalactiae, also known as Group B streptococcus, emerged in the 1960s as a leading cause of septicemia and meningitis in neonates. It is also an increasing cause of infections in adults with underlying diseases. To characterize regulatory elements in this species we performed a genome-wide transcription start site (TSS) profiling and whole-transcript sequencing. TSS were identified by using a differential RNA-seq strategy, based on selective Tobacco Acid Pyrophosphatase (TAP) treatment and adapter ligation, which differentiates primary transcripts and processed RNAs. The accuracy and sensitivity of TSS identification were increased by combining differential RNA-seq analyses under eight conditions corresponding to variations in growth conditions and genetic backgrounds. Whole-transcript sequencing used a two-step adaptor ligation-based directional RNA-seq protocol and was performed under two experimental conditions with triplicate experiments to assess variations in gene expression in response to an acid stress
